Hollis Explorer User Manual - page 63
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Abnormal readings could include:
1. A reading fixed at zero or any other number when you are breathing
directly onto the sensor face with the rebreather disassembled.
2. An abnormally high reading during a dive.
NOTE: Under CE conditions after approximately 50 minutes
at 40 m at 1.6 l of CO
2
(very high workload) in 4 °C/39.2 °F it
should read 5 mb.
3. Readings that change up and down (not in one direction). This could
be a faulty sensor or a faulty connection into the Sensor Module.
The CO
2
sensor will benefit from calibration at the start of a dive sequence
and if the sequence is longer than 1 week, at the start of each new dive
week. When having not been used for over a month or if you suspect a
bad reading (see additional notes on filter care) a calibration must be done
prior to diving.
It is good practice for the user to check the approximate
validity of the CO
2
readings regularly, ideally prior to any dive. Simple
testing by breathing directly onto the sensor should see the reading rise
within approximately 1 minute.
Also exposure to clean fresh outside air
should give a reading in the order of 0.4 mB. The unit will respond faster
with the filter removed. So the user must familiarize themselves with the
operation and assembly of the system to be confident the device is work-
ing correctly. Consult your Hollis dealer if in doubt.
WARNING: If you wish to calibrate the unit you must ensure
you are in fresh ventilated (outside) air. DO NOT calibrate in a
closed room. The calibration method is discussed above and is
detailed step by step in the pre-dive sequence.
ELECTRICAL CONNECTION
The connector for the CO
2
sensor is imbedded into the Sensor Module
next to the 3 x O
2
sensors.
NOTE: If moisture is present when this connection is mated,
then contact corrosion may occur. This may give false read-
ings on the CO
2
sensor.
It is vital this connection is kept clean. hollis approved contact cleaner or
3
.1
4
!